U.S. patent application number 09/749721 was filed with the patent office on 2001-07-12 for device for sensing and locating objects hidden behind accessible surfaces of architectural structures.
This patent application is currently assigned to The Stanley Works. Invention is credited to Bijawat, Viresh, Powers, Russell H., Wakefield, David L..
Application Number | 20010007420 09/749721 |
Document ID | / |
Family ID | 22444848 |
Filed Date | 2001-07-12 |
United States Patent
Application |
20010007420 |
Kind Code |
A1 |
Bijawat, Viresh ; et
al. |
July 12, 2001 |
Device for sensing and locating objects hidden behind accessible
surfaces of architectural structures
Abstract
A hidden object sensor is described which senses and locates
hidden objects hidden behind a surface of an architectural
structure. The sensor includes sensing elements for sensing live
wires behind the accessible surface, and separate sensing elements
for respectively sensing metal and non-metallic objects behind the
tested surface. A microprocessor alternates between the use of the
various sensing elements and their associated circuits to detect
live wires, metal objects, or wood studs. Visible and audible
indicators are provided for indicating the device's mode of
operation and the locations of sensed hidden objects.
Inventors: |
Bijawat, Viresh; (North
Haven, CT) ; Wakefield, David L.; (North Haven,
CT) ; Powers, Russell H.; (Newington, CT) |
Correspondence
Address: |
Pillsbury Winthrop LLP
Intellectual Property Group
East Tower, Ninth Floor
1100 New York Avenue, N.W.
Washington
DC
20005-3918
US
|
Assignee: |
The Stanley Works
|
Family ID: |
22444848 |
Appl. No.: |
09/749721 |
Filed: |
March 8, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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09749721 |
Mar 8, 2001 |
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09130471 |
Aug 7, 1998 |
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6211662 |
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Current U.S.
Class: |
324/67 |
Current CPC
Class: |
G01V 3/15 20130101 |
Class at
Publication: |
324/67 |
International
Class: |
G01R 019/00 |
Claims
What is claimed is:
1. A hand-held hidden object sensor for sensing a location of
objects hidden behind a surface of an architectural structure, said
sensor comprising: an indicator for indicating a location of first
and second object types hidden behind a surface; sensing circuitry
for sensing said first and second object types hidden behind said
surface of said architectural structure; an indication activation
mechanism for causing the indication by said indicator of the
location of said first object type as sensed by said sensing
circuitry and precluding a concurrent indication of said second
object type; and a housing supporting said indicator, said sensing
circuitry, and said indication activation mechanism.
2. The hand-held hidden object sensor of claim 1, wherein said
first object type comprises a live wire carrying 110 or 220 Volts
AC and said second object type comprises an object not carrying a
voltage or current.
3. The hand-held hidden object sensor according to claim 1, wherein
said first object type comprises a metallic object and said second
object type comprises a non-metallic object.
4. The hand-held hidden object sensor according to claim 1, wherein
said indicator comprises a visible indicator and an audible
indicator, said visible indicator comprising an array of light
emitting elements, said audible indicator comprising a tone
generator.
5. The hand-held hidden object sensor according to claim 1, wherein
said sensing circuitry comprises a live wire circuit for sensing
live wires carrying at least 110 or 220 Volts AC, a metal circuit
for sensing metal objects, and a wood circuit for sensing wood
objects; said hand-held hidden object sensor further comprising a
calibration activation mechanism for causing the calibration of
said metal circuit and said wood circuit, said calibration
activation mechanism deactivating said wood circuit when said wood
circuit is not successfully calibrated, said indication activation
mechanism causing the indication by said indicator of a
"metal-only" indication when said wood circuit is deactivated.
6. The hand-held hidden object sensor according to claim 1, wherein
said first object type comprises live wires carrying 110 or 220
Volts AC, and said sensor further comprising a live wire
deactivating mechanism for bypassing the sensing and indication of
said live wires where the user anticipates static electricity
accumulating on said surface of said architectural structure and
knows said architectural structure is devoid of live wires.
7. A hand-held hidden object sensor for sensing a location of
objects hidden behind an architectural surface, said sensor
comprising: a housing comprising a contact surface for contacting
said architectural surface and a manually engageable portion to be
held by a user's hand during operation to scan said sensor across
said architectural surface while said contact surface remains in
contact with said architectural surface, said housing further
comprising a marking mechanism positioned and operable to place a
mark on said architectural surface, said mark on said architectural
surface corresponding to the location of an object located behind
said architectural surface; an indicator for indicating the
location of a sensed object; sensing circuitry for sensing the
sensed object behind said architectural surface; and an indication
activation mechanism for causing the indication by said indicator
of the location of said sensed object when said housing is at a
position corresponding to said location of said sensed object and
said contact surface remains in contact with said architectural
surface.
8. The hand-held hidden object sensor according to claim 7, wherein
said marking mechanism comprises a resilient flexible member and a
scribe pointed toward said architectural surface while said
contacting surface remains in contact with said architectural
surface, said resilient flexible member responding to a user's
finger by moving toward said architectural surface and causing said
scribe to place a mark on said architectural surface at a location
in line with an edge of said object being located.
9. The hand-held hidden object sensor according to claim 8, wherein
said scribe comprises a rigid object comprising a sharp apex
pointing toward said architectural surface while said contact
surface of said housing remains in contact with said architectural
surface.
10. The hand-held hidden object sensor according to claim 9,
wherein said rigid object comprises a rigid apex portion in the
shape of a cone.
11. The hand-held hidden object sensor according to claim 8,
wherein said resilient flexible member comprises a plate arranged
substantially parallel with said architectural surface while said
contact surface remains in contact with said architectural surface,
said plate being secured at a first end to a portion of said
housing and being unsecured at an end opposite said first end, and
said scribe being located on a side of said plate facing toward
said architectural surface while said contact surface remains in
contact with said architectural surface.
12. A hand-held hidden object sensor for sensing and locating
objects hidden behind an architectural surface, said sensor
comprising: a housing comprising a contact surface for contacting
said architectural surface and a manually engageable portion to be
held by a user's hand during operation to scan said sensor across
said architectural surface while said contact surface remains in
contact with said architectural surface, said housing further
comprising an axis corresponding in position to a sensed edge of an
object being sensed and located by said hand-held hidden object
sensor, and a mid-stud indicating marker spaced from said axis by a
predetermined distance equal to 1/2 the width of a standard wall
stud; an indicator for indicating the location of a sensed object;
sensing circuitry for sensing the location of said sensed object
behind said architectural surface; and an indication activation
mechanism for causing the indication by said indicator of the
location of said sensed object when said housing is at a position
corresponding to said location of said sensed object and said
contact surface remains in contact with said architectural
surface.
13. The hand-held hidden object sensor according to claim 12,
wherein said predetermined distance is 7/8 inches, and wherein said
mid-stud indicating marker comprises a protruding portion.
14. A method for sensing and locating objects hidden behind a
surface of an architectural structure, using a hand-held hidden
object sensor, said method comprising: sensing for first and second
object types hidden behind said surface of said architectural
structure; and indicating a location of said first object type
sensed; and precluding a concurrent indication of said second
object type.
15. The method according to claim 14, wherein said first object
type comprises a live wire carrying 110 or 220 Volts AC and said
second object type comprises an object not carrying a voltage or
current.
16. The method according to claim 14, wherein said first object
type comprises a metallic object and said second objects type
comprises a non-metallic object.
17. The method according to claim 14, wherein said indication of
the presence and location of said first or second object types
causes the illumination of an array of light emitting elements and
the generation of a tone.
18. The method according to claim 14, further comprising causing
the calibration of a metal circuit and a wood circuit, each
provided within said sensor, and deactivating said wood circuit
when said wood circuit is not successfully calibrated and causing
the indication of a "metal-only" indication when said wood circuit
is deactivated.
19. The method according to claim 14, further comprising
deactivating a live wire circuit to bypass the sensing and
indication of live wires carrying 110 or 220 Volts AC where a user
anticipates problems with static electricity accumulating on said
architectural surface and knows said architectural surface is
devoid of live wires.
20. A method for marking a position on an architectural surface
while using a hand-held hidden object sensor for locating objects
hidden behind the architectural surface, said method comprising;
placing said sensor so that a contact surface thereof contacts said
architectural surface; and scanning said sensor across said
architectural surface while said contact surface remains in contact
with said architectural surface; and depressing a marking mechanism
positioned on said sensor against said architectural surface to
place a mark on said architectural surface, the mark corresponding
to the location of said object sensed and located behind said
architectural surface.
21. A method for sensing and locating objects hidden behind an
architectural surface and for locating a center point of a stud
hidden behind said architectural surface, said method comprising:
identifying the edge of said stud hidden behind said architectural
surface which corresponds to an edge marking provided on a housing
of said sensor; and identifying the center point of said standard
wall stud as a point along said architectural surface which is
identified by a mid-stud indicating marker carried by said housing
of said sensor and spaced from said edge marking by a predetermined
distance equal to 1/2 the width of a standard wall stud.
22. The hand-held hidden object sensor according to claim 1,
wherein said indicator is further capable of indicating the
location of a third object type.
23. The hand-held hidden object sensor according to claim 22,
wherein said first object type comprises a live wire, said second
object type comprises metal, and said third object type comprises a
non-metallic object.
Description
FIELD OF THE INVENTION
[0001] The present invention is related to devices that will sense
for and locate objects hidden behind accessible surfaces, such as
walls, ceilings, and floors, of architectural structures.
DESCRIPTION OF BACKGROUND INFORMATION
[0002] There are several types of existing sensing devices for
sensing and locating objects behind walls and other building
surfaces. For example, U.S. Pat. No. 4,859,931 (Yamashita et al.)
discloses an electronic detector comprising both a capacitive
sensor and a magnetic field sensor. The capacitive sensor is
provided to locate non-metallic objects behind a wall surface, and
the magnetic field sensor is provided to locate metallic objects
behind a wall surface. U.S. Pat. No. 5,438,266 (Tsang) discloses an
instrument for locating buried conductors. The instrument utilizes
a signal generator and a coil having a substantially vertical axis
coil attuned to pick up odd and even harmonics of a fundamental
frequency of a periodic test current, thereby allowing the accurate
location of buried conductors. U.S. Pat. Nos. 5,352,974 and
5,619,128 (both to Heger) each disclose stud sensors which utilize
capacitive sensors for locating studs hidden behind a wall or other
structural surface.
[0003] Zircon Corporation markets a multifaceted stud finder device
called the VideoScanner.TM. 5.0 Model No. 54014. This device
detects wood, metal, and live electrical wires hidden behind walls,
floors and ceilings having conventional cross-sections. The device
has normal and deep scan settings in one mode and a metal setting
in another mode. Thus, the device can be set to scan for studs
using a normal or deep scan setting, or it can be set to scan for
metal objects. With either mode--the normal/deep scan settings or
the metal setting, the device is first calibrated. To calibrate the
device for sensing hidden objects, the activation switch is pressed
and held down, and a ready indicator will appear on an LCD once the
device has been calibrated. The activation switch is held down
during scanning of the device along the applicable surface. Once
the device is calibrated, it may be scanned to locate hidden
objects such as wood or metal studs in the normal and deep scan
settings, or metal objects in the metal setting. The device is
further provided with a portion which allows continuous AC voltage
detection. It will detect either 110 or 220 volts AC present in a
live electrical wire hidden behind the applicable building surface.
Once the voltage has been detected, the device will display a
flashing voltage icon.
SUMMARY OF THE INVENTION
[0004] The present invention is provided to improve upon devices
for sensing and locating objects hidden behind structural surfaces,
such as hand-held stud finding devices. An object of the present
invention is to provide such a sensing device that will
continuously sense for and locate both wooden and metal wall studs
hidden behind wall and other structural surfaces made of such
materials as plaster board. Another object of the present invention
is to provide such a sensing device that will further locate metal
rebars in concrete walls. Yet another object is to provide a
sensing device which automatically increases sensitivity during
calibration to most accurately sense and locate metal bars that are
located behind the accessible surface.
[0005] A further object of the present invention is to provide a
hidden object sensing and locating device that can locate live
wiring behind accessible wall and other structural surfaces, where
such surfaces are formed by materials such as plaster board or
concrete. A further object of the present invention is to provide a
wall stud sensing device with a convenient marking mechanism for
marking on the applicable surface one or more spots that coincide
with and indicate the position and dimensions of an object hidden
behind the surface. Yet another object of the present invention is
to provide a wall stud sensing device which utilizes an intelligent
hierarchical approach to simplify the operation of the device in
detecting and locating (and distinguishing between) live wires,
metal objects, and non-metallic objects.
BRIEF DESCRIPTION OF THE DRAWINGS
[0006] The above and other objects, features, and advantages of the
present invention are further described in the detailed description
which follows, with reference to the drawings by way of
non-limiting exemplary embodiments of the present invention,
wherein like reference numerals represent similar parts of the
invention throughout the several views, and wherein:
[0007] FIG. 1A is a perspective view of a hidden object sensor in
accordance with an embodiment of the present invention;
[0008] FIG. 1B is an end view of the illustrated sensor;
[0009] FIG. 1C is a bottom view of the illustrated sensor;
[0010] FIG. 1D provides a partial cross-sectional view of the
sensor-taken along the lines A-A as depicted in FIG. 1C;
[0011] FIG. 2 comprises a view of a wall surface 32 being scanned
by a hidden object sensor 10;
[0012] FIG. 3 is a block diagram of the electronic circuitry 60 of
the illustrated sensor; and
[0013] FIG. 4 is a flowchart representing the process by which the
illustrated hidden object sensor 10 will perform its various
functions.
DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENT
[0014] The present invention is directed to a hidden object sensor
for sensing and locating objects hidden behind an accessible
surface of an architectural structure, such as a wall, ceiling, or
floor surface of a dwelling or other type of building. Referring
now to the drawings in greater detail, FIG. 1 illustrates in a
perspective view, an exemplary embodiment of a hidden object sensor
10 comprising a back surface (see FIG. 1D) which is substantially
planar, and a top surface having a generally convex cross-section.
The illustrated sensor 10 comprises on its left side an on-off
switch 12 and on its right side, a live wire switch 14. A belt clip
16 is provided at one end on the top side of sensor 10. A plurality
of LEDs 24 are arranged along a common axis flush with the outer
surface of the illustrated sensor 10 and in line with its
longitudinal axis. Sensor 10 has a resilient but flexible marker
member 18 provided at an end opposite belt clip 16. Resilient
marker member 18 comprises a pencil hole 22 and is formed in the
shape of a triangle comprising an apex that coincides with the
central longitudinal axis of sensor 10. Rectangular recesses 18a,
18b extend downward from each sloped edge of the triangular-shaped
resilient marker member 18 in a direction parallel to the
longitudinal axis of sensor 10. Recesses 18a, 18b add to the
flexibility of a central portion of resilient marker member 18, and
further assist in targeting a specific location identified by
sensor 10 along the structural surface being scanned.
[0015] A pin marker 20 is centered within the central portion of
resilient marker member 18, and thus also coincides with the
longitudinal axis of sensor 10. Pin marker 20 may comprise, for
example, a sharp apex protruding from the bottom planar surface of
resilient marker member 18 and thus facing toward the surface to be
scanned. The user can use a free finger such as the index finger to
press down on the central portion of resilient marker member 18 to
cause the sharp apex of pin marker 20 to create a hole within the
structural surface, thereby identifying the position of a located
object hidden behind the structural surface. The sharp apex of pin
marker 20 may comprise an integral part of resilient marker member
18 which may be formed, for example, using a press molding
technique. Resilient marker member 18 may, for example, be formed
from a sheet of tin or brass alloy, or, in the alternative, it may
comprise a piece of fiber-reinforced molded plastic. In any event,
resilient marker member 18 should be of a material that is
resilient yet sufficiently flexible to allow a user to press pin
marker 20 into the scanned surface with little effort. It should
continue to return to its original position even after repeated
flexing of the central portion of resilient marker member 18. Note
that when the central portion of resilient marker member 18 is in
its non-flexed position as shown in FIG. 1B, the apex of pin marker
20 will be spaced from the scanned surface, as is evident in FIG.
1B.
[0016] A plurality of LEDs (visible indicators) are positioned in
tandem in line with the longitudinal axis of the illustrated
sensor. They comprise a yellow metal-only detection mode indication
LED 26, a red edge indication red LED 28a, plural red graduating
red LEDs 28b-28d, and a green ready indication LED 30. The hidden
object sensor 10 in the embodiment illustrated in FIGS. 1a-4 uses
electronic signals to identify and precisely locate the positions
of studs, joists, metal or live AC wires hidden behind structural
surfaces formed by drywall, concrete, and other common building
materials. Once the edge of a hidden object has been detected,
sensor 10 provides both audible and visible indications to allow
the user to easily pinpoint the center position of the hidden
object. The built-in pin marker 20 or pencil hole 22 may be used to
easily mark the object position on the wall surface.
[0017] FIG. 3 is a block diagram of electronic circuitry 60 which
facilitates the operation of the illustrated hidden object sensor
10. Plural sensing elements 38, 40, and 42 are secured within the
housing of sensor 10 so as to be in alignment with the sensor's
longitudinal axis for providing information indicative of the type
of object hidden behind the applicable building surface and its
location. Sensing element 38 is provided for sensing the existence
and location of live wires. Sensing element 40 is provided to sense
the presence of metal objects behind the surface. Sensing element
42 is provided to sense studs behind the applicable structural
surface. By way of example, sensing element 38 may comprise an
antenna or other sensing element for responding to electric or
magnetic fields which will be present near live wires carrying 110
or 220 volts AC. Sensing element 40 may comprise a magnetic field
sensor such as that disclosed in U.S. Pat. No. 4,859,931 (Yamashita
et al.). Sensing element 42 may comprise a standard capacitive
sensor for sensing hidden studs behind wall and other building
surfaces.
[0018] Live wire circuit 44 may comprise amplifying circuitry
narrowly tuned to coincide with a frequency on the order of 50-60
Hz, and having a threshold voltage level of approximately 90 V, to
thereby signal the presence of live wires carrying greater than 90
V and having a frequency of between 50-60 Hz. Metal circuit 46 may
comprise circuitry as provided in the metallic object detection
section disclosed the Yamashita et al. patent.
[0019] Wood circuit 48 may comprise sensing and calibration
circuitry such as that disclosed in the Yamashita patent, or as
described in other stud sensing devices such as either of the Heger
Patents (U.S. Pat. Nos. 5,619,128 and 5,352,974). Each of live wire
circuit 44, metal circuit 46, and wood circuit 48 is connected to a
microprocessor 52 which executes a process in accordance with the
flowchart shown in FIG. 4. Microprocessor 52 is further connected
to one or more visible indicators 50 and one or more audible
indicators 54. Audible indicator (s) 54 may comprise a speaker (not
shown). In the illustrated embodiment, visible indicator (s) 50
comprise LEDs 24 as shown in FIG. 1A.
[0020] In operation, the illustrated sensor 10 is first calibrated
and then is used to scan a structural surface to identify objects
hidden behind that surface. During calibration, the sensor 10 is
scanned across the structural surface in a manner similar to when
sensor 10 is scanned for purposes of identifying and locating
hidden objects. Different calibration processes are executed
depending upon whether the unit will be used for detecting and
locating wood or metal. Before calibration, live wire detection
switch 14 should be put in the "ON" or "OFF" position. However, the
user may wish to put the live wire switch 14 in the "ON" position
for the desired operation unless the user is sure that there are no
live wires present behind the structural surface being scanned.
[0021] When calibrating for wood, sensor 10 is firmly held flat
against the applicable surface. The user will then depress the
"ON-OFF" switch on the left hand side of sensor 10 and release.
Sensor 10 must then be held without any movement until the green
ready indication LED 30 flashes. Then, the user will sweep sensor
10 across the tested surface in the manner illustrated in FIG. 2
until a long beep is heard and a green ready indication LED 30
remains "ON." At that moment, the unit is calibrated and ready for
detection of wooden studs. Sensor 10 will sound three separate
beeps if no stud was detected by wood circuit 48, thus indicating
that wood circuit 48 could not be calibrated. At that point, wood
circuit 48 is shut off, and the "metal-only" yellow indication LED
26 will be illuminated.
[0022] When calibrating for the detection of metal objects, sensor
10 is held firmly against the surface to be tested, and the
"ON-OFF" switch is pressed and released. Sensor 10 is placed over a
location where a metal object is known to exist, and the unit is
turned on. When green LED 30 starts to flash, sensor 10 will be
set. Metal circuit 46 will set its sensitivity to the necessary
depth. It will then only indicate whether a metal object exists at
the set depth or closer. The actual depth will vary depending upon
the type and size of the metal object being detected.
[0023] Once sensor 10 is calibrated, to detect wood studs, the unit
is slid slowly across the surface in a straight line, as shown in
FIG. 2. As the unit moves closer to the left edge 36 of wood stud
34 (or to the right edge of wood stud 34 in the situation where the
device is being scanned toward the left to detect the right edge)
one or more red LEDs 28a-28d will be illuminated, starting with
lower-most red LED 28d when sensor 10 is far from left edge 36 and
including successive additional ones of LEDs 28c-28a until the
final LED 28a is illuminated--thus indicating the coincidence of
the center position of sensor 10 with the stud's left edge 36.
[0024] The position of left edge 36 will coincide with the position
of pencil hole 22 and pin marker 20 of resilient marker member 18.
At this point, a pencil or pin marker 20 may be used to mark the
position on the wall surface corresponding to edge 36 of stud 34.
The dimensions and position of stud 34 should be double-checked by
repeating the above steps while sliding sensor 10 from the right
side of stud 34, making additional markings indicating the stud's
right edge location on the wall surface. The mid point between the
two marks will indicate the stud's center.
[0025] When detecting for metal objects, the unit is calibrated as
described above for metal detection, and the unit is scanned in the
same manner described for detecting wood, as shown in FIG. 2, until
the red LEDs start to illuminate in the same manner. When an edge
of a metal object such as a metal stud or plate is detected, the
unit will sound short double beeps and it will flash green LED 30
and steadily illuminate red LEDs 28a-28d signalling the object's
location. The edge of the detected metal object may be marked on
the wall surface. Sensor 10 may be scanned from the opposite
direction, and an additional marking may be made on the wall
surface identifying the location of the opposite edge. The mid
point between the markings indicates the center point of the
detected metal object.
[0026] For locating deep metal objects up to a maximum depth
allowed by metal circuit 46, metal circuit 46 of sensor 10 may be
calibrated by holding sensor 10 away from any wall surface and
pressing the "ON-OFF" switch 12 momentarily. The user will then
wait until green LED 30 stops flashing, at which point sensor 10 is
set for detecting and locating metal objects at a maximum distance
from the wall surface, and the wood circuit 48 has been shut off,
as indicated by yellow "metal only" LED 26 being illuminated.
[0027] When metal circuit 42 is calibrated to detect metal objects
at a maximum depth sensitivity, metal objects close to the wall
surface may seem to have a very wide width as indicated by sensor
10. To ascertain the true edges of the metal object being detected,
sensor 10 may be placed at the approximate center of the indicated
area and be re-calibrated for the appropriate depth of that
specific metal object. Sensor 10 may then be re-scanned across that
area from each side of the metal object, to locate the edges of
that object.
[0028] Sensor 10 will detect live wires as sensor 10 is scanned
across the structural surface being tested, provided live wire
switch 14 is in the "ON" position, and ON-OFF switch 12 is pressed
momentarily at the beginning of scanning. No specific calibration
is required for detecting live wires. When a live wire is detected,
sensor 10 will sound triple short beeps, a green LED 30 will be
illuminated and all red LEDs will flash in a rotating pattern. The
live wire indication, as described, will override both wood and
metal indications. Note that shielded live wires contained in metal
conduits, casings, or behind metallized walls or thick, dense
walls, will not be detected by live wire circuit 44.
[0029] Sensor 10 further comprises extending "horn" portions 17 at
either side of resilient marker member 18. Each horn portion 17
comprises an inner surface 17' which is spaced precisely 7/8 inches
from the center axis of sensor 10, which coincides with pin marker
20 or pencil hole 22. This facilitates the prompt location of the
center of a standard wood stud which is 1 and 3/4 inches in width.
The user may simply mark the center point of the stud on the wall
surface by using the inner surface 17' of the extending horn
portion 17 as a guide.
[0030] FIG. 1C provides a view of the bottom of sensor 10, which is
the side of sensor 10 which comes in contact with the surface being
scanned. As shown in FIG. 1C, hidden object sensor 10 comprises an
outer housing, which includes a substantially planar contact
surface 11 which will come in direct contact with the surface being
scanned. A removable battery (not shown) for powering the device's
circuitry may be accessible via a battery door 13.
[0031] The view shown in FIG. 1C shows the bottom side of resilient
marker member 18, including pin marker 20 and pencil hole 22. FIG.
1D shows a partial cross-sectional view of hidden object sensor 10,
illustrating a cross section of resilient marker member 18 along
the lines A-A. As shown in FIG. 1D, pin marker 20 may comprise a
metallic scribe inserted into a recess of resilient marker member
18. The metallic scribe may comprise, for example, a brass insert
having an apex portion 19a, a flange 19b and a cylindrical insert
portion 19c which may comprise threads or may be fastened to the
recess provided within resilient marker member 18 by glue or cement
or by another process, such as insert molding. The recess provided
within resilient marker member 18 is of a shape to accommodate both
the cylindrical protruding portion 19c as well as flange portion
19b of the metallic insert.
[0032] FIG. 4 illustrates the process performed by the sensing
circuitry 60 shown in FIG. 3, as controlled by microprocessor 52.
At an initial step S2, the process will commence upon powering on
of sensor 10 by depressing switch 12. The sensor will then generate
one beep in step S4, and calibration will be commenced for metal
detection as indicated at step S6. Frequency calibration will occur
within wood circuit 48 at step S8, and upon commencement of both
the metal detection calibration and stud detection calibration,
microprocessor 52 will cause the green LED to be flashed, as
indicated at step S10. At step S12, microprocessor 52 will allow
wood circuit 48 to search for a stud for up to 5 seconds. At that
point, as indicated at step S14, the green LED will be constantly
illuminated.
[0033] At step S16, a determination is made as to whether wood
circuit 48 has successfully calibrated itself for stud detection.
If not, the process will proceed to step S30, where the yellow LED
will be illuminated indicating that sensor 10 is in a metal-only
detection mode. If wood circuit 48 did successfully calibrate
itself to detect studs, the process will proceed to step S18, at
which point microprocessor 52 will cause a single beep to be
generated by the audible indicator 54, thereby signaling that
sensor 10 is ready to detect studs, metal objects, and live wires.
At step S20 a timer will commence. At step S22, a determination is
made as to whether ON-OFF switch 12 has been pressed again. If it
has, the process will be forwarded to step S58 at which point
microprocessor 52 will shut sensor 10 off. If the ON-OFF switch
(i.e., the power key) has not been pressed again, the process will
proceed from step S22 to step S24, where a determination is made as
to whether the 3 minutes of time set at step S20 has expired. If
such time has expired, the process will proceed to step S58.
[0034] If the three minutes have not expired, the process will
proceed to step S26, where microprocessor 52 will inquire as to
whether an AC voltage of a sufficient level has been detected by
live wire circuit 44. If such a voltage level has been detected,
the process will proceed to step S28 where the appropriate AC
indications will be triggered via visible indicator 50 and audible
indicator 54. The process will then return to step S22. Note the
process will not be forwarded to step S50 if an AC (live wire)
indication is generated, as the device is designed so that it will
not identify the existence and location of a metal object or a stud
where a live wire exists. This serves as a safety precaution to
prevent the user from proceeding to insert a nail or screw into a
detected metal object or stud that may coincide in position with
the detected live wire. Only if there is no AC voltage detection as
determined at step S26 will the process proceed to step S50 and
then inquire as to whether a metal object has been detected by
metal circuit 46.
[0035] If a metal object has been detected by metal circuit 46, the
process will proceed to step S52 where a metal indication will be
triggered by microprocessor 52 via visible indicator 50 and audible
indicator 54 in accordance with the process as described above.
While a metal indication is taking place, and a metal object has
been detected by sensor 10, the process will not proceed to detect
a stud using wood circuit 48, and thus will not return to step S54
until and unless there has been no detection of an AC voltage at
step S26 and there has been no detection of a metal object at step
S50. When a metal object has been detected, the sensor 10 will
identify the fact that the object is metallic by generating short
double beeps with the audible indicator, flashing the green LED,
and steadily illuminating the red LEDs. To indicate a detected wood
stud a short repeating beep is generated while using the same
audible indicator steadily illuminating the same green LED and the
same red LEDs. If the process proceeded to determine if a stud was
detected at step S54, wood circuit 48 would also provide an
indication of the presence of an object behind the tested surface,
as wood circuit 48 uses a capacitive sensor which may very well
sense metal objects as well as wood objects. This would
unnecessarily create confusion, and would require that a separate
indicator such as a separate row of LEDs be provided for purposes
of simultaneously indicating that a stud exists as detected by the
capacitive sensor used by wood circuit 48.
[0036] To cut down on the cost of providing extra indicators and
LEDs and to cut down on the confusion encountered by the user, the
device of the illustrated embodiment is simplified. It includes
only one set of indicators for identifying hidden objects, and
detects for hidden objects in accordance with an intelligent
hierarchy. That hierarchy prioritizes the information provided to
the user so that the user is only provided with the most pertinent
and meaningful information at any given time. Thus, if an AC
voltage is detected, information will not be provided regarding the
location of a metal or wooden object hidden behind the tested
surface. The user only needs to concern his or herself with the
fact that there is a live wire behind the tested surface.
[0037] If there is no live wire behind the tested surface, the
sensor 10 may indicate the existence and location of a metal object
behind the tested surface via processing at step S50 and step S52.
If that is the case, the presence and location of that metal object
will be identified by the audible indicator and the single set of
LEDs 24 using a specific protocol--with the green LED flashing, the
red LEDs on and the audible indicator providing short double beeps.
The device will automatically avoid checking to see whether there
is a wooden stud where the device is already indicating the
existence and location of a metal object. The user need not be
concerned with whether or not a non-metallic object coincides with
the metallic object that has been detected.
[0038] If there is no live wire or metal object detected at either
step S26 or S50, the process will proceed to step S54 and check for
the existence and the location of a stud with the use of wood
circuit 48. If a stud is located, the appropriate indication
protocol will be triggered at step S56, thus causing the red LEDs
to be illuminated, and a short repeating beep, and the illumination
of a green LED to commence upon the coinciding of sensor 10 with
the stud edge.
[0039] Before sensor 10 will commence the detection and location of
objects behind a tested surface, it will perform a calibration for
metal detection as well as a calibration for stud detection at
steps S6 and S8. To further simplify the operation of the device
and the user's understanding of the types of objects behind the
tested surface, the device will indicate as a result of that
initial calibration when there are no non-metallic objects detected
behind the tested surface, and the device will automatically enter
into a metal-only sensing mode. When sensor 10 is in this mode, a
yellow LED 26 will be illuminated at step S30, and three beeps will
be generated by audible indicator 54 indicating that the device is
ready to detect metal objects and live wires behind the tested
surface, and that the device will not concern itself with
non-metallic objects, as no such non-metallic objects appear to be
present. At step S34 a three minute timer will be commenced. At
step S36 a determination is made as to whether the power key has
been pressed. If it has, the process will proceed to step S58, and
sensor 10 will be shut off. If the power key was not pressed, the
process will proceed to step S38 where a determination is made as
to whether three minutes have expired. If the three minutes have
expired, the process proceeds to step S58. If not, the process
proceeds to step S40, where a determination is made as to whether
live wire circuit 44 has detected a live wire. Here, the hierarchy
is set up so that if a live wire is detected, the appropriate
indication protocol is triggered by microprocessor 52 at step S42,
and the process will return to step S36. Only if no live wire is
detected at step S40, will the process proceed to step S44, at
which point metal circuit 46 will try to detect and locate a metal
object. Upon the detection and location of a metal object, the
appropriate indication protocol will be triggered by microprocessor
52 at step S46.
[0040] While the invention has been described by way of an
exemplary embodiment, it is understood that the words which have
been used herein are words of description, rather than words of
limitation. Changes may be made within the purview of the appended
claims, without departing from the scope and spirit of the
invention in its broader aspects. Although the invention has been
described herein with reference to particular elements, materials
and embodiments, it is understood that the invention is not limited
to the particulars disclosed. The invention extends to all
equivalent structures, mechanisms, elements and uses which are
within the scope of the appended claims.
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